[tex]A=\left(\begin{matrix}-1 & -4 \\0 & 6\end{matrix}\right)[/tex]

[tex]det(A)=\left|\begin{matrix}-1 & -4 \\0 & 6\end{matrix}\right|=-1\cdot 6-(-4)\cdot 0=-6-0=-6[/tex]

[tex]A^{-1}=\left(\begin{matrix}-1 & -4 \\0 & 6\end{matrix}\right)^{-1}=\frac{1}{-6}\cdot \left(\begin{matrix}6 & 4 \\0 & -1\end{matrix}\right)= \left(\begin{matrix}\frac{1}{-6}\cdot 6 & \frac{1}{-6}\cdot4 \\\frac{1}{-6}\cdot0 & \frac{1}{-6}\cdot(-1)\end{matrix}\right)=\left(\begin{matrix}-1 & -\frac{2}{3} \\0 & \frac{1}{6}\end{matrix}\right)[/tex]

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[tex]B=\left(\begin{matrix}4 & -2 \\-3 & 2\end{matrix}\right)[/tex]

[tex]det(B)=\left|\begin{matrix}4 & -2 \\-3 & 2\end{matrix}\right|=4\cdot2-(-2)\cdot(-3)=8-6=2[/tex]

[tex]B^{-1}=\left(\begin{matrix}4 & -2 \\-3 & 2\end{matrix}\right)^{-1}=\frac{1}{2}\cdot\left(\begin{matrix}2 & 2 \\3 & 4\end{matrix}\right)=\left(\begin{matrix}\frac{1}{2}\cdot2 & \frac{1}{2}\cdot2 \\\frac{1}{2}\cdot3 & \frac{1}{2}\cdot4\end{matrix}\right)=\left(\begin{matrix}1 & 1 \\\frac{3}{2} & 2\end{matrix}\right)[/tex]